Why is oil used in Thiele tube?

Why is oil used in Thiele tube?

Oil is poured into the tube, and then the “handle” is heated, either by a small flame or some other heating element. The shape of the Thiele tube allows for formation of convection currents in the oil when it is heated. These currents maintain a fairly uniform temperature distribution throughout the oil in the tube.

Where should you apply heat to the oil in the Thiele tube?

Heat the apparatus gently on the side arm of the Thiele tube with a microburner if available or Bunsen burner using a back and forth motion (Figure 6.15d).

Why must you heat the oil of the Thiele tube slowly and steadily if and accurate melting point is required?

It is important to heat the sample slowly using this method so that a thermal equilibrium can be established. Generally, you will heat the capillary tube to near melting point and then decrease the speed of the temperature increase so that you can observe when the sample melts.

Why is oil used instead of water in determining the melting point of the samples?

2Paraffin oil is used for determination of boiling point and melting point for the following reasons: It has a very high boiling point and so it can be used to maintain high temperatures in the boiling and melting point apparatus without loss of the substance.

How do you use the Thiele melting point tube?

Fill a small tube about half-full with sample and insert a capillary tube, closed end up. Attach the tube to a thermometer with a small rubber band. Insert the sample into a Thiele tube, so that the sample is near the middle of the oil. Heat the arm of the Thiele tube with a burner, gently and continuously.

Why Thiele tube method is better than distillation method?

The Thiele tube method is one of the simplest methods to determine a compound’s boiling point, and has the advantage of using small amounts of material (less than 0.5mL of sample). The tube is then allowed to cool, and the moment liquid is drawn into the capillary tube, the temperature is the compound’s boiling point.

How do you use Thiele tube?

Why does oil expand when heated?

When a solid is heated, its atoms vibrate faster about their fixed points. The relative increase in the size of solids when heated is therefore small. Liquids expand for the same reason, but because the bonds between separate molecules are usually less tight they expand more than solids.

Why is it important to heat the apparatus slowly and steadily when the temperature gets close to the MP range?

Why is it important to heat the sample slowly and steadily as the melting point temperature is approached? What is the effect of using to large a sample? Larger amounts will cause slower heating, and the MP range will be inaccurately large.

Why is it important to heat the sample slowly and steadily as the melting point temperature is approached?

It is essential to heat the sample slowly and steadily as the melting point temperature is approached in order to provide a sufficient amount of heat so that the sample melts rapidly.

What are safety precautions during oil handling, heating planning?

Safety precaution during oil handling, heating planning & optimization -oil tankers guideline Expansion Allowance: Before loading commences, consideration must be given to the temperature of the cargo being loaded and to the maximum temperature, which may be expected on the voyage.

How is temperature increase controlled in a Thiele tube?

When heating, the rate of temperature increase should be carefully controlled. Usually one holds the burner by its base and, using a small, gentle flame, moves the burner slowly back and forth along the bottom of the side arm of the Thiele tube.

How is Thiele tube heated in a microburner?

It is important that this rubber band be above the level of the oil (allowing for expansion of the oil on heating). Otherwise, the oil softens the rubber and allows the capillary tubing to fall into the oil. The Thiele tube is usually heated using a microburner with a small flame but a Bunsen burner can also be used.

What are the best precautions for handling flammable liquids?

Avoid using equipment with series-wound motors, since they are likely to produce sparks. Do not heat flammable liquids with an open flame. Steam baths, salt and sand baths, oil and wax baths, heating mantles and hot air or nitrogen baths are preferable. Minimize the production of vapors and the associated risk of ignition by flashback.